Furnace wall



June 23, 1931. c THAYER 1,811,373

FURNACE WALL Filed Oct. 11, 1927 5 Sheets-Sheet l A TTORNEY 5Sheets-Sheet 2 It. I! I b mv-: m m4 w 2 v Tl l fN TO B) 'ATTORN Y June23, 1931. H. c. THAYER FURNACE WALL Filed Oct.

June 23, 1931. H. c. THMFER FURNACE WALL Filed Oct. 11, 1927 5Sheets-Sheet 3 ATTORNEY H. C. THAYER A FURNACE WALL June 23, 1931.

Filed 001:. 11. 1927 5 Sheets-Sheet 4 'ATTOR 'EY June 23, 1931. 1 H. c.THAYER FURNACE WALL Filed Oct. 11, 1927 5 Sheets-Sheet 5 16 ATTOR EYPatented June 23, 1931 UNITED STATES PATENT OFFICE HOWARD C. THAYEB, OFJERSEY CITY, NEW' JERSEY, ASSIGNOR TO BERNITZ FURNACE APPLIANCE COMPANY,OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSA- OHUSETTS FURNACE WALLApplication filed October 11, 1927. Serial No. 225,522.

In modern boiler plants the temperatures created, run so high that ithas now become a common practice to use wall constructions or facings ofhighly refractory material and also to make some provision for coolingthe walls. If some means is not provided to cool the lining it willbecome heated to such a degree that its surface is softened or renderedsomewhat plastic so that slag and clinker will stick to it. When theseaccumulations are removed a part of the lining is chipped off and asthese operations are repeated from time to time the surface of the wallbecomes worn away to such an extent that the lining must be renewed.

One method of keeping the temperature of the lining below the point atwhich slag and clinker will adhere to it has been to embed pipes ortubes in the wall and to circulate water or steam through these pipes ortubes, the heat taken away from the wall by the water or' othercirculating medium being used in the-boiler. Such walls will be hereinreferred to as water cooled walls regardless of the circulating mediumused, the nature of the furnace, or the position in the furnace. J

The present invention is especially concerned with walls of this type.It aims to improve these wall constructions with a view to reducing theexpense of manufacturing them while still providing a thoroughlysatisfactory and highly efiicient wall structure. The invention involvesboth a novel wall construction and also novel units or elements for usein such walls. The nature of the invention will be readily understoodfrom the following description-when read in connection with theaccompanying drawings, and the novel features will be particularlypointed out in the appended claims.

In the drawings,

, Figure 1 is a front view of a. portion of a water cooled wallconstructed in accordance with this invention;

Fig. 2 is a cross-sectional view on the line 22, Fig. 1;

Fig. 3 is an elevation showing substantially the manner in which thewall shown in Fig.

2 would appear with the back casing and in- Fig. 5 is a perspective viewof one of the refractory blocks or bricks used in the wall shown in thefigures above described;

Fig. 6 is a perspective view of the clamp plate used with the brickshown in Fig. 5;

Fig. 7 is a perspective view of the bolt which preferably is used withthe clamp and brick shown in Figs. 5 and 6;

Fig. 8 is a. horizontal cross-sectional view showing, on a larger scale,a portion of the construction shown in Fig. 2;

Fig. 9 is a horizontal cross-sectional view on a relatively large scaleof the clamps which hold the tubes in alinement and shows the refractoryblocks in their cooperative relationship to these clamps;

Fig. 10 is a perspective view showing a portion of one of the clampingbars shown in Fig. 9;

Figs. 11, 12 and 13 are vertical cross-sectional views at the upper partof the wall showing different arrangements for supporting the tubes;

Figs. 14: and 15 are horizontal cross-sec-' tional views showingmodified embodiments refractory blocks or bricks 3 which protect thetubes at the front or fire side of the wall. Fastening devices includingclamping plates 4 cooperate with each block 3 to secure it to the tubes.At the rear of the tubes, and spaced from them, is a casing includingsheet metal panels'or sections 5 which are secured to and supported byupright means 6, and this in mind, the various details of theconstruction will be better understood. Referring more particularly toFigs. 3, 4, 9 and 10 it will be seen that the tubes 2 are held in theirroper positional-relationship to each other y a series of clamps, eachcomprising a bar 8 provided with a plurality of approximatelysemi-circular recesses, one. of which is best shown at 9 in Fig. 10.These recesses are designed to receive the tubes 2, as clearly shown inFig; 9. The tubes are clamped rigidly in these recesses by U-bolts 10,each bolt embracing a tube and having its legs extending through the bar8. Nuts 12 are threaded on the ends of these legs and serve to draw thebolts firmly backward so that the clamps may be secured very tightly tothe tubes. Preferably two U-bolts are used, one aboveland the otherbelow, the central projecting part of each clamping bar 8, as

clearly shown in Fig. 4. Several horizontal series of these clamps areused, two such series being shown' in Figs. 3 and 4, and one series isspaced longitudinally of the tubes from the other by a considerabledistance. Preferably the individual clamping bars 8 in the two seriesare staggered with refer ence to each other, as clearly show in Fig. 3.Consequently, these clamps secure the tubes of the wall in a. definitespaced relationship to each other and hold the tubes securely inalinement.

The refractory blocks 3 are mounted between the clamps 8-8, and a verysubstantial part of the weight of these blocks is supported by theclamps. These blocks are made of some highly refractory material,preferably silicon carbide.

Figs. 5 to 8, inclusive, show more clearly the various details ofconstruction of an individual block and the fastening means which holdsit in position in the wall. It will be seen from an inspection of theseviews that the block 3 includes a front wall a on which the face I)which is exposed to the fire is formed, the entire thickness of the walla serving to protect the tubes 2. Projecting rearwardly from this wall aand located between the tubes 2 is an extension or tongue 0, and thistongue has a T-shaped slot d formed tlierejthrough from side to side toreceive the head a of a bolt 14 which forms part of the fastening orclamping means for the blocks. The bolt 14 projects through the clampingplate 4 and a nut 15 threaded on the bolt cooperates with it and theplate 4 to draw the block 3 backwardly into contact with the tubes 2. Itwill be observed that the clamping plate 4 bridges two adjacent tubesand is provided withupright faces 16'16, Figs. 6 and 8, to bear againstthe tubes. The block 3 also has upright curved faces f to bear ing bars8, above referred to, to take at least a substantial part of thisWeight. This arrangement, however, makes a very solid substantialconstruction in which the parts are easily assembled and which providesfor the expansion and contraction of the indi-'' vidual blocks and ofthe tubes.

As above explained, the front face of the wall, or that exposed to thefire, is subjected to extremely high temperatures, and the chief purposeof the tubes 2 is to conduct a circulating medium whichtakes away aportion of this heat and thus holds the temperature of the lining belowthe point at whiqh the surface of the refractory blocks 3 will softenand permit clinker to adhere-to it. I have found that the heat transferfrom the refractory blocks to the tubes can be improved materially byusing a cement between the blocks and tubes which, instead of being aheat insulator, is a conductor of heat. Silicon carbide cementpreferably is used.

Referring to Fig. 8 it will be seen-that a very considerable part of thespace between each of the tubes 2 and the block 3 is filled in withcement 17. The sides ofthe tonguec are cut away or grooved vertically atthe rearward side of the faces ff .to provide s ace for this cement, asclearly shown in igs. 5 and 8, and I prefer, also, to provide horizontalgrooves g in these faces to assist in locking the cement in place. As afurther means of holding this cement while it sets the lower margin ofthe clamping plate 4 is provided with an inwardly extending flange 18,Figs. 4, 6 and 8, which closes up a part of the space between theclamping plate 4 and the block 3 at the lower portions of these members.

It is desirable to prevent any substantial leakage of airthrough thefurnace wall, and for this purpose I prefer to seal the joint betweenthe clamping, plates 4 and the tubes 2 by cement or in some equivalentway. As best shown in Figs. 6 and 8, the curved faces .16 of the plate 4which contact with the tubes are grooved, as indicated at 20, to receivecementor some suitable sealing material and thus close this verticaljoint. The horizontal. oints between adjacent clamps may also be sealedwith cement, asbestos tape, or other suitable material, as shown at 21in Figs. 3

and 4, and the same construction may be used between the ends ofadjacent clamping bars 8 and also between the upper and lower surfacesof these bars and the plates 4. It usually is preferable, also, to setthe blocks 3 in an air setting cement which closes the horizontal joints22, Figs. 1 and 4, although I preferto leave the vertical joints 23open.

Leakage'of air or gas through the Wall is further prevented by thecasing 5. shown this casing is supported by upright beams 66, Fig. 2,and the sheet metal panels 5 extend from the flange of one beam to theflange of the next adjacent beam. At each beam the margin of the panelor section is clamped in position by an angular strip 23, Fig. 2, apacking stri 24 of asbestos or the like being interposed etween themargin of each sheet metal section and the flange of the beam. At,thehorizontal joints between the sections 5 inner and outer reinforcingbars 25 and 26, respectively, are used (see Figs. 2 and 4), these twobars overlapping the margins of' adjoining sections and being boltedtogether so that they clamp these margins securely between them. Theinner bar 25 is grooved to receive packings 27, Fig. 4, of asbestos orany other suitable material,-which make practically a gas tight-joint atthese points. There is relatively little difference in gas pressure atthe two sides ofthe wall, so that a construction of this character makespractically a gas tight wall.

The heat insulating material used between the rear casing 5 and the rearsurfaces of the clamping plates 4 may consist of any suitable material.A common construction is to use a layer of insulating cement at thebacks of the clamping plates and then a layer of rock wool between thislayer of cement and the casing 5.

' Fig. 14 shows a construction substantially like that shown in Fig. 8except that the T- shaped slot in the block 3 which receives the bolt 14is located vertically instead of horizontally, and this bolt is embeddedin heat insula-tlng cement which assists in protecting it from theaction of the hot gases and high temperatures.

Another modification is shown in Figs. 15

and 16 in which the rearwardly extending tongue of the block 3 isprovided with a. slot 29 to receive a bar 30 which cooperates with thefins 31 of the tubes 2' to fasten the blocks in their cooperativerelationship to the tubes. In this construction, also, the verticalgrooves 32 inthe block which are provided to receive cement 17 stop at ashort distance above the bottom of the block. In other words, the lowerart of this block is provided with a short ange, the upper side of whichterminates at the line 33, Fig. 16, and which serves to retain thecement while it is setting.

Fig. 17 shows a construction much like that shown in Fig. 15 except thatthe bar 30 is tapped to receive screws 33-33 which bear against the fins31.

In the construction shown in Figs. 18 and 19 the rearwardly extendingtongues of the refractory blocks 3 are simply grooved verticallyat eachside to receive the fins 31, the fins thus acting to lock the blocks inplace.

In some of these blocks the faces are plain, as shown in Fig. 5, whilein others, as for example in Figs. 14, 18 and 19, the faces arecorrugated, one face construction being preferred in some installationsand another un-- der different conditions.

Another modification is shown at Fig. 20 in which refractory blocks 34of quite a different shape are used, and at the side of the tubes 2opposite the fire faces of the blocks another refractory block 35 is setinto recesses formed in adjacent blocks 3434. The block 35 bears againstthe rear side of the tube and cooperates with flanges on the blocks34-34 at each side of it to lock them against the tubes.

Figs. 11, 12 and 13 show arrangements which may be provided forsupporting the tubes to permit longitudinal expansion and contraction ofthem. In Fig. 11 the upper ends of the tubes are joined to a header 36which is supported at intervals by heavy springs 37. In manyconstructions, however, the tubes are curved at their upper ends, asshown'in Figs. 12 and 13, and where such a construction is employed Iprefer to support the tubes at points adjacent to one header in fixedpositions by clamps or yokes 38 which are secured to one of the beams ofthe wall. This holds the tubes firmly in position while allowing them toexpand away from this supporting point and at the same time relieves thejoint between the tubes and the header 36 of the weight of the tubes.

While I have described the invention as applied more especially to atypical steam boiler installation, it will be understood that wallsembodying this invention are applicable to a great variet of furnacestructures and that, consequent y, the medium circulated through thepipes ortubes embedded in the wall may consist of any one of a. greatforded by the use of a heat conducting cement to unite the refractoryblocks and tubes.

circumstances, a cement which is a conductor of heat. By properlyselecting or mixing the cement the rate of heat transfer to the'tubescan be controlled. A silicon carbide cementaifords a relatively highrate of heat transfer, while a fire clay cement afi'ords only a very lowrate. The two cements, however, can be mixed together in suitableproportions to make a degree of heat conductivity which will varygreatly. Other cements or mixtures of cement also can be used. The heatconductivity can be proportioned to that of the refractory blocks sothat the rate of heat transfer can be suited to the conditions obtainingin any particular installation, and the results desired'in suchinstallation.

An important advantage of this feature of the invention consists incontrolling the thermal storage in the refractory blocks so that thetemperature at the face of the block will be regulated more accurately,this bein de-' sirable not only from the standpoint of preserving therefractory wall or lining, but also incontrolling the temperatures a.short distance away from the fire face of the wall such a manner as toproduce eflicien-t combustion. 1

Having thus described my invention, what I desire to claim as new is:

1. In a'furnace wall, the combination of a series of tubes, clampssecured to said tubes and constructed to hold said tubes spaced fromeach other and in a definite positional relationship to each other,refractory blocks protecting said tubes and clamps, and additional meansfor securing said blocks to said tubes.

2. In a furnace wall, the combination of a series of tubes, clampssecured to said tubes and constructed to hold said tubes spaced fromeach other and in a definite positional relationship to each other, saidclamps being spaced longitudinally of the tubes, each clamp comprising abar havin a series of recesses to receive a plurality of a acent tubes,bolts extending through each bar and embracing said tubes and serving todraw them into said rccesses, and refractory blocks bearing againstsaidtubes between said clamps.

3. In a furnace wall, the combination of a seriesof upwardly extendingtubes, clamps secured firmly to said tubes but spaced apartlongitudinally of the tubes and serving'to hold the tubes in spacedrelationship, each clamp comprising a bar having recesses to re ceive aplurality of ..djacent tubes and bolts embracing said tubes and servingto draw them into said recesses, certain of sald clamps being arrangedin staggered relationship to others, and refractory blocks protectingsaid tubes between said clamps.

4. In a furnace wall, the combination of a series of upwardly extendingtubes adapted to conduct a cooling fluid, a header to which said tubesare connected, a plurality of substantially horizontal clamps securedrigidly to said tubes and spaced apart longitudinally ofthe-tubes andserving to hold the tubes spaced from each other, and blocks of siliconcarbide held in contact with said tubes between said clamps, the weightof said blocks being at least partly supported by the clamps.

5. In a furnace wall, the combination of a series of upwardly extendingtubes, clamps secured firmly to said tubes but spaced apart.

longitudinally of the tubes and serving to hold the tubes in spacedrelationship to each other, and refractory blocks bearing against saidtubes between said clamps and protecting said tubes and clamps, theclamps supporting a substantial part of the weight of said blocks, andmeans independent of said clamps for holding said blocks in theiroperative relationship to said tubes.

6. In a furnace wall, the combination of a series of upwardly extendingtubes; a plurality of clamps secured to said tubes and serving to holdthe tubes in spaced relationship to each other; each clamp comprising ahorizontal bar located. immediately beside said tubes but extendingtransversely to them andmeans for securing the tubes to said bar; and aseries of refractory blocks located immediately above said clamps inprotective relationship to said tubes.

'7. In a furnace wall, the combination of a series of upwardly extendingtubes; a plurality of clamps secured to said tubes and serving toholdthe tubes in spaced relationship to each other; eachclamp comprisinga hor1- zontal bar located immediately beside said tubes but extendingtransversely to them, U-bolts embracing said tubes, respectively, andhaving threaded shank portions extending through the bar, and nuts .onsaid shanks cooperating with the U-bolts to secure the tubes rigidly tothe bar; and refractory blocks located immediately above said clamps inprotective relationshi to said tubes.

HgWARD G. THAYER.

